Concrete beamless building construction



Nov. 28, 1967 s. B. ZUKAS CONCRETE BEAMLESS BUILDING CONSTRUCTION 5Sheets-Sheet 2 Filed Jan. '7, 1964 Inventor s ayzz'f j u (/6 Nov. 28,1967 s. B. ZUKAS 3,354,593

CONCRETE BEAMLESS BUILDING CONSTRUCTION Filed Jan. 7, 1964 I 5Sheets-Sheet 5 1967 s. B. ZUKAS CONCRETE BEAMLESS BUILDING CONSTRUCTION5 Sheets-Sheet 4 Filed Jan.

I npenlor Nov. 28, 1967 s. B. ZUKAS 3,354,593

CONCRETE BEAMLESS BUILDING CONSTRUCTION Filed Jan. 7, 1964 v 5Sheets-Sheet 5 M I nvenlor United States Patent Oliice 3 ,354,593Patented Nov. 28, 1967 3,354,593 CONCRETE BEAMLESS BUILDING CONSTRUCTIONSaimon Ber Zukas, Drayton House, Gordon St, London, England Filed Jan.7, 1964, Ser. No. 336,175 Claims priority, application Great Britain,Jan. 10, 1963, 1,191/63 2 Claims. (Cl. 52--251) This invention relatesto a system of construction for beamless structures and aims atsimplicity, cheapness where labour costs are high and adaptability tosite requirements.

The system in accordance with the invention results in the constructionof structures comprising a number of columns devoid of corbels or otherlateral protuberances and the space between which is covered by slabssupported by the columns or by neighboring slabs without the aid ofbeams or the like.

The invention consists, specifically in a system of buildingconstruction for beamless structures comprising columns made up ofprecast concrete sections joined end to end and of precast concreteslabs, the slabs comprising one series (hereinafter called cantileverslabs) supported directly by the column sections and providingcantilever supports for a second series of slabs (hereinafter calledbridging slabs) spanning the gaps between adjacent cantilever slabs andframing rectangularly openings each closed by an in-filling slab. Thecolumn sections are of uniform cross-section throughout their lengthexcept that their upper ends are rebated to provide seatings for thecantilever slabs which are cast with central holes of smallercross-section than the column sections and are provided with reinforcingbars through the said holes. Each column section is rendered monolithicwith a cantilever slab by grouting of the cavity defined by the centralhole therein.

The column sections and the slabs can be pre-cast in the workshop and betransported to the building site or can be precast on the site. It is,of course, advantageous to have as small a number of different sizes ofcolumn sections and slabs as possible. The dimensions of these depend,naturally, on the height between successive floors of the structure andthe spacing of the columns. If the columns have a square pitch, i.e.,are disposed at the corners of squares, the slabs can be all of the samesize. That, however, is not essential. For example, the cantilever slabscan be made all of the same size, the bridging slabs all of the samedilferent size and the in-filling slabs of the same but still differentsize. The size of the slabs is governed largely by the lifting apparatuswhich is availa- Y ble at the building site.

The invention finds its greatest utility in the construction ofstructures of moderate size in which the spacing of the column is, say,from 12 to 16 feet. In that case, slabs of a uniform size of 6* to 8feet square can be used, each weighing approximately to 2 tons andpresenting no great lifting problem.

The columns can, of course, have a rectangular (nonsquare) pitch. Inthat case, the cantilever slabs are most usefully made square and theother slabs are suitably elongated.

In the preferred form of the invention, the cantilever slabs are madesquare with a side length of to 7 of the pitch of the columns.

As the cantilever slabs have to resist a substantial bending moment dueto the weight of the slabs and the load borne by the floor, theirreinforcement is important and should consist of bars passing in twoperpendicular directions through the holes in them.

The columns also have to resist bending, and care must be given to theirreinforcement where they pass through the cantilever slabs. In thepreferred form of the invention, the joint between column section isreinforced by splice bars located in sleeves provided in the ends of thesections and having ducts leading from the blind ends to the outsidewhich serve as grouting inlets.

The columns being devoid of corbels or the like, the under side of theslabs can provide a completely flat surface extending from column tocolumn. In the preferred form of the invention, the slabs are rebated attheir peripheries to provide scarf joints; the floors formed by theslabs having level upper and under faces.

In the course of construction of a building, the cantilever slabs andthe columns can be subjected temporarily to uneven loading. This can beavoided, however, by a method of assembling the columns and slabs whichconsists in lowering each cantilever slab on to the end of a columnsection, temporaly supporting it at each of its corners, lowering thebridging slabs on to the cantilever slabs while the latter are sosupported and lowering the in-filling sla'bs on to the cantilever andbridging slabs, this operation being repeated for the construction ofeach successive floor. Preferably, the temporary supports are in theform of tie rods formed of two lengths connected together byturn'buckles enabling their overall length to be adjusted.

An example of the practical application of the invention to theconstruction of a fairly light multifloor structure will now bedescribed in some detail with reference to the accompanying drawings inwhich:

FIGURE 1 is a sectional plan of part of the building;

FIGURE 2 is a perspective underneath plan of part of the building;

FIGURE 3 shows a joint between a column and a cantilever slab;

FIGURE 4 illustrates diagrammatically a'method of assembling the columnsand slabs;

FIGURES 5 and 6 are sections taken respectively on the lines VV and VIVIin FIGURE 1;

FIGURE 7 shows the detail of a joint between two slabs; and

FIGURE 8 illustrates a corner of a floor bay.

As shown in FIGURES 1 and 2, the building has a series of columns 10-which are disposed to form a rectangular grid. In this particularinstance, the four columns shown are at the corners of a square. Eachcolumn 10 directly supports a cantilever slab A which projects laterallyfrom it in all directions. The gaps, between the cantilever slabs Aalong the axes of the grid are spanned by a series of bridging slabs B,and the gap framed by a set of four bridging slabs B is closed by anin-filling slab C.

The columns 10 extend throughout the height of the building, floorsbeing provided at desired levels, as shown in FIGURE 3, whichillustrates one particular form of joint between a column and acantilever slab.

The column shown in FIGURE 3 is made up of a series of pre-castconcentrate sections 12. Each section is of uniform cross-section alongits length and is provided at the top end with a periperal rebate 13.Each section is also provided at each end with sleeves 14 defining holesfor the reception of splice bars 16.

Each cantilever slab A is rectangular in plan square as shown. It isprecast in concrete with a central rectangular hole 18 so that the slabcan be seated on the column rebate 13. The hole 18 tapers upwards. Theslab has a bar reinforcement 20 in the region of its upper surfacerunning in both directions across the hole 18.

In forming the joint shown in FIGURE 3, the slab A is first placed inposition on the top of the lower column section 12. Then four splicebars 16 are passed down between the reinforcement bars, are grouted, andthe hole 18 filled with concrete. To complete the joint, the uppercolumn length 12 is lowered .on to the splice bars 16 and is grouted inposition, grout holes 22 and blow holes 24 being provided for thispurpose.

The joint thus formed is substantially monolithic.

To provide extra resistance to the bending moment exerted at thejunction between the column and Shah, each splice bar 16 can beprovided, as shown, with a steel washer 26 which rests on the top of theslab.

FIGURE 4 illustrates a very convenient method of assembling the slabs toform ,a floor, four phases I, II, III and IV being shown.

At phase I, a lower floor has been completed and a cantilever slab A isbeing lowered into position on to a column section 12 as explained inconnection with FIG- URE 3. Each of the slabs has passing through it,near each of its corners, a tie rod 28 provided with a pair of stops 30,the slabs being formed with holes 31 at their corners as shown inFIGURE 1. The slab A having been set on the column, the tie rods 28 areconnected together by turnbuckles 32 as shown at phase II. By adjustmentof the turnbuckles, the slab can be accurately levelled and be heldfirmly in position until the joint between it and the lower columnlength 12 is completed in a later operation.

The next operation is to lower the bridging slabs B into position, inwhich they rest on the cantilever slabs, which is illustrated at phaseIII. During this operation, the cantilever slabs A are held firmly inposition by the tie rods 28 in spite of the uneven loading of thoseslabs. The placing in position of the in-filling slab C, presents noproblem and is not illustrated in FIGURE 4.

At phase IV the new floor is completed and has received a new columnsection 12 so that the construction of a further floor can be stated atphase I. For this purpose, the turnbuckles 32 are removed, the upper tierods 28 are left hanging by their stops 30, and the lower tie rods 28are removed and they or another set of tie rods are passed through andleft hanging from the new cantilever slab A to be assembled. Theprocedure from that point onwards is as described in connection withphase I. Thus, the tie rods and turnbuckles are repeatedly used and onlya relatively small number of them need be provided. The stops 30, can beremoved from the tie rods; or they can be collapsible so that they can,when desired, be passed through the holes in the slabs; or the stops canbe permanent and the holes in the slabs so shaped that the rods can bewithdrawn by rotating them a half turn.

As has been explained, the cantilever slabs A may be permanentlyunevenly loaded at those columns which define the outside of thebuilding. That uneven loading can be balanced by special reinforcementin the columns and by the collars 26 provided .on the vertical splicebars as shown in FIGURE 3. In any event, it is advisable to reinforceeach column length so that it acts as a vertical cantilever anchored atits base.

The slabs which define the boundaries of the floor can be .of specialconstruction so that they do not project substantially outward beyondthe columns on which they are supported. In that case, they would bedimensioned so as to be supported by neighboring cantilever slabs andwould not themselves serve as cantilever or supporting slabs.

FIGURES and 6 show respectively the joints between the cantilever slabsA and the bridging slabs B and the joints between the in-filling slabs Cand the bridging slabs B. All these joints are scarf joints. Thecantilever slabs are similarly rebated in their upper surfaces shown at36 along their four edges. The bridging slabs are rebated in their lowersurfaces as shown at 38 along the two opposite edges which are alongsidethe cantilever slabs so that the bridging slabs rest on the cantileverslabs. The infilling slabs C are rebated in their lower faces as shownat 40 (FIGURE 6) along their four edges while the bridging slabs arerebated in their upper surfaces as shown at 42 along the edges which arealongside the in-filling slabs so that the in-filling slabs rest on thebridging slabs.

The depth of rebating is such that the floor formed by the slabs haslevel upper and under surfaces.

The joints between the slabs are finished off as shown in FIGURE 7. Ascan be seen, a number of rods 46 held in position by stirrups 48 arelaid in the gaps between the upper edge of the slabs. These rods extendcontinuously round the slabs and the gaps are filled in with grout,which may be of quick setting cement so as to render the floorsubstantially monolithic.

As already mentioned, the slabs at the outer boundaries of the structurebuilt as described above will be unevenly loaded. This state of affairscan be remedied, if desired, as shown in FIGURE 8, by the use of analternative boundary arrangement in which there are columns 50 whichcarry trimming slabs E, F, and G, the columns being near the outer edgesof those slabs.

This system for building construction can be employed for the groundfloor or base from which a building rises, the columns supporting thefloor or base then being piles stuck into the ground; this is especiallyapplicable to the smaller types of buildings, such as single or twostorey private dwellings and it replaces conventional foundations of thekind involving trench excavation and the placing of footings.

Above the base or raft constructed in this way the building may rise inthe same manner as is described above using columns, cantilever slabs,bridging slabs and in-filling slabs.

In some cases it may be desirable to use a base or raft constructed :bya method embodying the invention and to construct the rest of thebuilding in some other manner for example a conventional masonry andtimber structure.

I claim:

1. A beamless building floor supported on (a) columns,

(1) each column consisting of precast sections having an upper and alower end, the upper end of each column section being joined to thelower end of a succeeding one of the column sections, and

(2) each column section being of uniform crosssection throughout thelength thereof but being rebated at the upper end;

(b) rectangular cantilever slabs supported directly by the columns andmutually spaced from each other to define gaps therebetween,

(3) each cantilever slab being precast with a central hole of smallercross-section than the crosssection of the column sections,

.(4) the cantilever slab holes being aligned with the upper ends of thecolumn sections and the rebated upper ends thereof constituting seatsfor the cantilever slabs, and

(5) said slabs having fiat underfaces extending to said columns;

(c) reinforcing bars in said cantilever slabs and extending across thecentral holes thereof;

(d) grouting filling the central holes of the cantilever slabs andsurrounding the reinforcing bars,

(6) each cantilever slab being rendered monolithic with an associatedone of the column sections by said grouting;

(e) rectangular bridging slabs spanning the gaps between adjacent onesof the cantilever slabs, the cantilever slabs providing cantileversupport for the bridging slabs, and the bridging slabs definingrectangular openings therebetween; and

( f) rectangular in-filling slabs closing said openings,

(7) all of said slabs forming continuous flat upper and under faces.

2. The beamless building structure of claim 1, wherein the upper ends ofsaid column sections define sleeves, and splice bars are mounted in saidsleeves and extend through said central holes of the cantilever slabs,being embedded in said grouting whereby the joint between the upper endof one column section and the lower end of a succeeding one of saidcolumn sections is reinforced.

References Cited UNITED STATES PATENTS =Eisen 52260 Borg 52252Cifll'lilli 10 Murren 522 63 Contini 5273 6 FOREIGN PATENTS 1956Australia. 1962 Australia.

OTHER REFERENCES FRANK L. ABBOTT, Primary Examiner.

R. A. STENZEL, Assistant Examiner.

1. A BEAMLESS BUILDING FLOOR SUPPORTED ON (A) COLUMNS, (1) EACH COLUMNCONSISTING OF PRECAST SECTIONS HAVING AN UPPER AND LOWER END, THE UPPEREND OF EACH COLUMN SECTIONS BEING JOINED TO THE LOWER END OF ASUCCEEDING ONE OF THE COLUMN SECTIONS, AND (2) EACH COLUMN SECTIONSBEING OF UNIFORM CROSSSECTION THROUGHTOUT THE LENGTH THEREOF BUT BEINGREBATED AT THE UPPER END; (B) RECTANGULAR CANTILEVER SLABS SUPPORTEDDIRECTLY BY THE COLUMNS AND MUTUALLY SPACED FROM EACH OTHER TO DEFINEGAPS THEREBETWEEN, (3) EACH CANTILEVER SLABS BEING PRECAST WITH ACENTRAL HOLE OF SMALLER CROSS-SECTION THAN THE CROSSSECTION OF THECOLUMN SECTIONS, (4) THE CANTILEVER SLABS HOLES BEING ALIGNED WITH THEUPPER ENDS OF THE COLUMN SECTIONS AND THE REBATED UPPER ENDS THEREOFCONSISTING SEATS FOR THE CANTILEVER SLABS, AND (5) SAID SLAMP HAVINGFLAT UNDERFACES EXTENDING TO SAID COLUMNS;